Dyeing of acrylonitrile fibers and composition for same



nited tates DYEING OF ACRYLQNITRILE FIBERS AND COMPOSITION FOR SAME No Drawing. Application October 12, 1953, Serial No. 385,682

16 Claims. (Cl. 855) The present invention relates to the art of dyeing. More particularly, it relates to a novel dye assistant, to a process for preparing the dye assistant, to a dye bath containing the dye assistant, and to a method of dyeing synthetic fibers utilizing the dye bath of the invention.

In recent years, there has been developed a large number of textile fibers which are prepared from materials classed generally as synthetic linear polymers. Specific examples of these new fibers are the acrylic fibers, the polyester fibers, the polyamide fibers (nylon), the vinyl fibers and others of similar origin. They are currently sold under a variety of tradenames including Orlon, Dacron, Dynel, Acrilan, Saran, Vinyon, etc.

From the very inception of the new synthetic fibers it was found that, in general, they did not possess a strong affinity for the known dyes. Consequently, it has been necessary to devise entirely new methods of dyeing in order to achieve the desired quality of dyeing. One of the new dyeing methods, which has been devised for the acrylic fibers, is the so-called cuprous ion method. This method consists in adding a cupric salt and a reducing agent to an aqueous dye bath containing the fiber and an acid dye and maintaining the bath at or very near the boiling point during the dyeing operation. It is known that in this method the cupric salt and the reducing agent react within the bath to produce cuprous ions. It is theorized that the cuprous ions are then absorbed by the acrylic fiber thereby creating an afiinity for the dye, which is normally an acid or directdye.

The results obtainable by the cuprous ion method were found to be improved by the addition to the dye bath of a small quantity of a swelling agent, the most widely used of which are the phenylphenols, particularly paraphenylphenol which is sold to the dyeing industry under the general tradename Purasist.

Despite the apparent success of the cuprous ion method, it has several disadvantages, the greatest of which results from the fact that the addition of the reducing agent to the dye bath is very critical and as a result it has been necessary to devise rather elaborate methods for controlling the addition of the reducing agent. Thus, the cuprous ion method is undesirably complicated.

The dyeing of other types of the new synthetic fibers has required different methods. For example, polyester fibers were found to have some afiinity for the acetate dyes and it was found that fairly good dyeings could be obtained by the addition to the dye bat-hof other materials such as swelling agents. However, even with the use of dye assistants, the dyeing of polyester fibers is usually slow-and the quality of dyeing is not as good as might be desired. Furthermore, the dyeing of dark shades has been virtually impossible.

In the dyeing of polyamide fibers, the acid dyes'have been found to be the most suitable but, even with the use of these dyes, it has been necessary to employ a dye assistant in order to achieve the satisfactory dyeing. Here again, however, the dyeings are generally slower atent O ice than is desirable and are not as satisfactory as the dyeings usually obtained in the case of the more easily dyed natural fibers.

The dyeing of other types of fibers such'as those prepared from vinylidene chloride and similar vinyl polymers has also been difiicult. Acetate dyes are generally used in dyeing these fibers but still the dyeings have been slower and poorer than the dyeings obtained on natural fibers.

It is an object of the present invention to provide a novel dye assistant which is capable of improving the dyeing of any of the hereinabove described synthetic fibers to the extent that faster dyeings and deeper shades of color are obtainable.

Other objects of the invention include the provision of a process for the preparation of the dye assistant, the provision of a dye bath containing the dye assistant, and a method of dyeing synthetic fibers which utilizes the dye bath of the invention.

The invention resides in part in the discovery ofa dye assistant comprising a mixture of a dimer of furfuryl alcohol and a phenolic compound having the formula:

wherein X is at least one radical selected from the group consisting of hydrogen, hydrocarbon, hydroxy phenyl alkyl, carboxy and halogen radicals, a is an integer from 1 to 3 and b is an integer from 1 to 2, the sum of a and b not exceeding 3.

The invention also resides in part in the discovery of a novel and convenient process for the preparation of the dye assistant described above. I

The invention further res-ides in the discovery that the addition of the hereinabove described dye assistant to a dye bath of any of the types previously used in the dyeing of synthetic fibers improves the bath to the extent that better dyeings are made possible.

The dimer of furfuryl alcohol, to which reference has been made, can be obtained by known procedures. It is known, for example, that synthetic resins can be prepared by the polymerization of furfuryl alcohol in the presence of an acid catalyst. If a strong .acid is used as the catalyst is an amount sufiicient to give a substantially completely condensed and polymerized resin, the resultant polymer is characterized by hardness, toughness and chemical resistance. However, in the manufacture of synthetic resins from furfuryl alcohol, it is customary to proceed through two separate and distinct stages as is disclosed in British Patent No. 595,208. In the initial stage, furfuryl alcohol is partially polymerized by employing a weak acid catalyst or small amounts of a strong acid catalyst. The product at this stage of the polymerization is termed an intermediate polymer of furfuryl alcohol and it consists essentially of a dimer of furfuryl alcohol dissolved or colloidally dispersed in residual monomeric furfuryl alcohol. It is this dimer of furfuryl alcohol with which the present invention is concerned. However, for the sake of completing the description, it is explained that ordinarily in the manufacture of a synthetic resin from furfuryl alcohol, the'intermediate polymer is converted by the addition of further quantities of acid to a hard infusible, insoluble polymer which represents the second stage of the resin. These second stage resins are not, however, within the contemplation of the present invention. a

In the partial polymerization of furfuryl alcohol, there are a number of means which can be employed to control the reaction in order to prevent the conversion of the furfuryl alcohol to the infusible, insoluble stage. For ex- 3 ample, a quantity of acid may be added to furfuryl alcohol to nitiate an exothermic reaction and if the acid is a weak acid, the reaction will stop of its own accord at the intermediate stage. If a strong acid is employed as a catalyst, the reaction can be controlled by using only small amounts of the catalyst so that the reaction will automatically terminate before the formation of an infusible, insoluble polymer. In another method, an excess of a strong acid, preferably phosphoric acid, may be employed and the reaction may be terminated at the intermediate stage by, 1

neutralization of the acid with alkali. In still another method, the reaction may be controlled by performing the reaction in the presence of water or by adding water at the appropriate stage. It is not, however, necessary to use an acid catalyst because monomeric furfuryl alcohol can also be polymerized to an intermediate stage by boiling the alcohol under reflux for a few hours or even by storing the monomer at ordinary temperatures for a few months. Still another method of polymerizing the alcohol to an intermediate stage comprises passing an alternating current through the alcohol at the boiling point of the alcohol in this manner an intermediate polymer can be obtained in as short a time as two hours. Further details of the preparation of intermediate polymers of furfuryl alcohol may be found in British Patent No. 587,350, British Patent No. 595,208, and U. S. Patents Nos. 2,345,966, 2,456,628 and 2,553,677. In preparing the dimer of furfuryl alcohol to be employed as an ingredient of the dyeing assistant of the present invention, any of the methods mentioned above can ,be used. Also, in preparing the dimer any catalyst can be used such. as, for example, phosphoric acid, sulfuric acid, hydrochloric acid, paratoluene sulfonic acid, acetic acid, and the like as has been described in the art.

The conditions of reaction described herein for the preparation of a product containing a dimerof furfuryl alcohol are applicable to mixtures of monomeric furfuryl alcohol containing up to approximately by weight of furfural, and, hence, since such a dimer is, in fact, a furfuryl alcohol dimer, that term as used herein includes a dimer made from furfuryl alcohol which may contain up to approximately 15% by weight of furfuryl admixed therewith.

As above stated, the partial polymerization of furfuryl alcohol according to any of the above-described procedures leads to the formation of an intermediate polymer which consists essentially of a dimer of furfuryl alcohol dispersed or dissolved in unreacted monomeric furfuryl alcohol, although other lower polymers of furfuryl alcohol, such as the trimer and tetramer may also be present in relatively small amounts. The dimer is believedto-be the compound, 5-furfuryl-furfuryl alcohol.

In making up the dye assistant, the crude intermediate polymer of furfuryl alcohol is preferably used as is. However, if desired, the dimer can be separated from the crude product, for example, by distillation, and used in the pure form but, as can be seen, this latter procedure is generally not as desirable because of the expense and inconvenience involved.

The phenolic compound for which a generic formula has been given above may be any of a large number of phenolic compounds. To mention but a few by way of example, there areincluded within the formula such com pounds as paracymylphenol, tertiary butyl catechol, salicylic acid, pyrogallic acid, alpha-methyl-benzyl-O-phenylphenol, ortho, meta and para-phenylphenol, phenol, cresol, 4-tertiary-butyl-Z-phenylphenol, octylphenol, nonylphenol, 4,4 isopropylidene-bis (2-isopropylphenol), resorcinol, thymol as well as ortho, meta and para-chlorophenol, p,p-isopropylidenediphenol, and p,p-sec.-butylidenediphenol.

Of the phenolic compounds mentioned above, the phenylphenols, and principally paraphenylphenol, are preferred. I am aware that paraphenylphenol has been used as a swelling agent to assist in dyeing operations, but whatever benefit this compound is capable of providing in the dyeing of synthetic fibers can be materially increased by employing it in combination with the furfuryl alcohol dimer according to the teachings of the present invention. There are also certain economical advantages attributable to the invention. For example, while paraphenylphenol has been used previously as a dye assistant in the dyeing of synthetic fibers, it has usually been necessary to employ a finely divided form of the compound which has been specially prepared. On the other hand, the utilization of paraphenylphenol in combination with the dimer of furfuryl alcohol according to my invention permits the use of the crude paraphenylphenol of commerce which is only about one-half as expensive as the specially prepared compound.

In preparing the dye assistant, it is an advantage that the relative proportions of the ingredients are widely variable and excellent results have been obtained using dye assistants in which the ratios of phenolic compound to furfuryl alcohol dimer vary from a major proportion of one compound to a major proportion of the other. In selecting proportions of the two ingredients, the controlling f-act seems to be that the furfuryl alcohol dimer serves, in some synergistic capacity, as an activator for the phenolic compound and that it is the latter compound which actually assists in the dyeing. Consequently, it is generally necessary that the dye assistant contain only a trace, i. e., about 1% by weight, of the dimer relative to the amount of phenolic compound. On the other hand, an excess of dimer is not at all harmful and good dyeing assistants have been prepared in which the amount of dimer even exceeds the weight of phenolic compound. However, while the amounts of dimer and phenolic compound can be widely varied with respect to each other, it is the phenolic compound, as above stated, which is believed to be the principal active ingredient of the dye assistant whereas the dimer of furfuryl alcohol is an activator for the phenolic compound. Accordingly, the amount of dye assistant to be incorporated in the dye bath will ordinarily be based on the amount of phenolic compound in the dye assistant and, therefore, if the dye assistant contains a relatively small proportion of phenolic compound, a greater quantity of the dye assistant may be required in order to assure the exhaustion of the dye bath. Further explanation of the amount of dye assistant to be used in a dye bath will be given hereinafter.

The fact that only a trace of dimer need be present in relation ,to the amount of phenolic compound is particularly true when a solvent for the dimer is also present in the dye assistant. A solvent which is particularly applicable for this purpose is monomeric furfuryl alcohol. Accordingly, in the preferred embodiment of the invention wherein the crude partial polymerization product of furfuryl alcohol is used in making up the dye assistant, monomeric furfuryl alcohol is inherently present and the presence of the monomer makes possible the use of extremely small quantities of dimer, in comparison to the amount of phenolic compound, in the dye assistant. However, if one wishes to use a pure distilled dimer, for example, as in ingredient of the dye assistant, solvents other than monomeric furfuryl alcohol which have the efiect of lowering the amount of dimer required in relation to the amount of phenolic compound can be employed. Solvents which are suitable for this purpose are, in their approximate order of efiicacy, decanediol, phenylmethyl carbinol, 4-hydroxy-1,3-dimethylbenzene, B-phenylethanol, n-decyl alcohol, ethylhexanediol, neopentyl glycol, ethyl hexanol, methyl cyclohexanol, cyclohexanone, methyl isobutyl carbinol, triethylene glycol, n-octyl alcohol, cyclohexanol, n-heptyl alcohol, benzyl alcohol, and n-hexyl alcohol.

It is stressed at this point that no solvent for the dimer is necessary provided sufiicient dimer is present in the dye assistant. A suggested lower limit, when no solvent is present, is about 10% by weight of the phenolic compound.

In using my dye assistant in a dyeing operation, the individual ingredients of the dye assistant may be added to the dye bath separately or they may be first admixed and then added to the dye bath. However, there are several advantages involved in first preparing the mixture. There is a special advantage, for instance, in using the phenolic compound as a catalyst for the polymerization of monomeric furfuryl alcohol so that, in such a case, the dye assistant of the invention is produced directly while at the same time providing a convenient method for polymerizing the alcohol. It has been found that by utilizing this preferred procedure for the preparation of the dye assistant, the acidity of the phenolic compound is generally low enough to catalyze the reaction of a few percent of the monomeric furfuryl alcohol to the dimer even though relatively large amounts of phenolic compound is employed. Furthermore, the reaction conditions employed are generally mild enough so that the phenolic compound itself does not react with the furfuryl alcohol. To illustrate, the addition of a phenylphenol to monomeric furfuryl alcohol results in the promotion of an exothermic condensation reaction and the direct formation of about 3% by weight of the dimer of furfuryl alcohol, based on the total weight of furfuryl alcohol, without the necessity of taking precautions to prevent the complete polymerization of the alcohol. The same is true of the other phenolic compounds although the percentage of dimer formed in each instance will vary according to the acidity of the phenol. In some cases, the dye assistant obtainedin this manner is a solid material in which monomeric and dimeric furfuryl alcohol are absorbed upon solid particles of the phenolic compound. However, in other cases, i. e., when the phenol is a liquid or is soluble in monomeric furfuryl alcohol, the dye assistant is a. homogeneous liquid.

In those cases where the furfuryl alcohol is polymerized by a method other than using the phenolic compound as a catalyst, it is also advantageous to admix the phenolic compound with the dimer of furfuryl alcohol prior to formulating the dye bath. This preference is particularly strong in the case of certain solid phenolic compounds which are ordinarily ditficultly soluble or dispersible in a dye bath. For instance, the ordinary paraphenylphenol of commerce is a solid material which cannot be used very successfully in a dye bath because of its insolubility and large particle size. Therefore, as above stated, the dyeing industry has normally used a specially prepared form of paraphenylphenol in which the compound is very finely divided. I have found, however, in the practice of the invention that the ordinary paraphenylphenol of commerce can be used very satisfactorily in the preparation of my dye assistant by milling together the paraphenylphenol and furfuryl alcohol dimer with a diluent in any conventional type of milling apparatus, such as a colloid mill, to produce a dye assistant in the form of a dispersion. Apparently, this milling of the dye assistant is sufficient to decrease the particle size of the paraphenylphenol to the extent that is becomes more readily dispersible in the dye bath. In this embodiment where the dimer and phenolic compound are milled together there should be used a sufficient amount of water or solvent to obtain a milled product of thick, liquid consistency. An emulsifying agent may also be used to aid in the formation of a uniform dispersion.

In cases where the phenolic compound is employed as a catalyst for the furfuryl alcohol polymerization, as described above, it is also preferable to mill the phenolcontaining reaction product, whenit is a solid, to form a dispersion by the same technique employed in the formation of a dispersion when the paraphenylphenol is added separately.

The dye bath of the invention is prepared by adding a quantity of the hereinabove described dye assistant to any of the dye baths which have heretofore been used in the dyeing of synthetic fibers. In the preparation of the dye bath, the ingredients with the exception of the dye assistant, are conventional and the selection of ingredients is dependent upon the type of fiber that is to be dyed.

In the dyeing of acrylic fiber, for example, any of the acid dyes or direct dyes which have heretofore been found satisfactory in the cuprous ion method of dyeing can be used to prepare the dye bath of the invention. These are well recognized classes of dyes which are commercially available and which are characterized by their application from an acidic dye bath. Such dyes include, for example, Anthraquinone Blue SKY (C. I. 1088), Anthraquinone Green GN (C. I. 1078), Orange II (C. I. 151) Quinoline Yellow PN (C. I. 802), Anthraquinone Blue RA, Anthracene Blue WR (1, 2, 4, 5, 6, S-hexahydroxyanthraquinone), as well as many other dyes. Suitable dyes are also sold under various tradenames, such as Roracyl Orange R, Roracyl Dark Green B, Pontacyl Fast Red AS (C. I. 176), Pontacyl Rubine R (C. I. 179), Roracyl Violet 2R, Cuprofix Yellow G concentrated (C. I. 620), and Cuprofix Violet ZBL (Pr. 429). It is also desirable in the dyeing of acrylic fiber that the dye bath contain a water-soluble cupric salt similar to the cupric salts employed in the cuprous ion method. The concentration of the dye and the cupric salt can be the same as the concentrations used in the cuprous ion method. It is to be emphasized, however, that unlike the cuprous ion method there is not required the addition of any reducing agent to the dye bath.

In the dyeing of nylon, the dye bath may contain any of those dyes which have previously been used to dye this fiber. Generally, an acid dye is preferred and any of the acid dyes specifically mentioned above can be used. In the case of this fiber, however, no cupric salt is necessary and the only essential ingredients of the dye bath are the dye itself and my dye assistant.

In the case of Dacron and vinyl fibers, such as Saran, the acetate dyes are generally used and the dye assistant of the invention is used to replace any of the dye assistants which have been formerly used to improve the dyeing of these fibers. Examples of acetate dyes which can be used are:

Celanthrene Yellow GL (300%) (Prototype 534), Celliton Fast Pink RF New (l-hydroxy2-methoxy-4-amino- 9,10-anthraquinone), Celanthrene Cerise B, Latyl Violet B [l-hydroxy-4-(m-hydroxy methyl phenyl amino)-9,10- anthraquinone], Latyl Blue 2G, Eastman Blue GLF {1,8 dihydroxy 4 [p (2 hydroxyethyl)phenylamino] 5 nitro 9,10 anthraquinone}, and Interchem Blue BGLF-40.

Since the ingredients of the dye bath and the concentrations thereof are conventional except for my dyeing assistant, the primary consideration involved in making the dye bath of the invention is the amount of dyeing assistant to be incorporated therein. It is an advantage that the amount of dyeing assistant can be widely varied. Usually the amount of dyeing assistant is controlled by the amount of phenolic compound in the assistant since, as above explained, it is believed to be the phenolic compound that is the principal active ingredient of the assistant. It also appears that there is some relationship between the quantity of dye and the quantity of phenolic compound and that a certain minimum amount of phenolic compound, which will vary with the dye and dye assistant, is required in the bath in order to obtain exhaustion of the bath- Usually, this amount is in the neighborhood of by weight of the dye when dyeing pale shades and about 40% by Weight of the dye when dyeing very heavy shades. This does not mean, however, that it is necessary to use this minimum amount of dye assistant because any amount of dye assistant,,,however small, will improve the dye bath even though. exhaustion of the bath may not be obtained.

On the other hand, it is also possible to employ an amount of dyeing assistant in excess of the ,amount that is minimally. required to obtain exhaustion of the bath. However, the use of more dye assistant than is actually necessary is wasteful and expensive. Therefore, a sug gested practical and approximate upper limit on the amount of dye assistant is that amount which contains a quantity of phenolic compound not exceeding the weight of the dye. Summarizing, any amount of dyeing assistant is beneficial but, for practical purposes, it is generally not desirable to add to the dye bath an amount of dye assistant greater than that required to provide phenolic compound in a quantity equal to the weight of dye.

The method of dyeing provided by the invention comprises immersing a synthetic fiber in the dye bath hereinabove described. In its manipulative steps, the process is conventional and in accordance with conventional practice the dye bath is preferably maintained at its boiling point during the immersion of the fiber.

No precise limits of time required for the dyeing can be given since the time will vary with many factors such as the concentration of dye, the depth of shade desired, and the temperature of the dye bath. Thus, the time may vary from a few minutes to several hours. In practically every case, however, the dyeings obtainable in our process are more rapid than dyeings made in a dye bath which does not contain my dye assistant.

In the dyeing operation, no unusual precautions are necessary and satisfactory dyeings can be obtained quite rapidly by merely immersing the yarn or fabric to be dyed in the dye bath, and, preferably, maintaining the dye bath at the boiling point. Sufficient yarn or fabric can be dyed in this manner to substantially exhaust the bath. Any of the customary and conventional pieces of apparatus that are employed in the dyeing industry can be used. Suitable apparatus includes, for example, dye jigs, package dyeing machines, dye becks, and raw stock dyeing machines.

The following examples are given in order to illustrate the invention and its attendant advantages. Parts and percentages are by weight except otherwise specified.

Example 1 Into a reaction vessel equipped with a thermometer and reflux condenser, there was placed parts of monomeric furfuryl alcohol. The furfuryl alcohol was heated to its boiling point (approximately 168 C.) and parts of paraphenylphenol was added gradually to the furfuryl alcohol over a period of about 45 minutes. The initial addition of the paraphenylphenol caused an exothermic reaction as evidenced by an increase in the rate of boiling of the furfuryl alcohol, but as the addition of paraphenylphenol was continued, the exothermic reaction appeared to subside and the boiling point of the mixture rose. After all of the paraphenylphenol had been added, the mixture in the vessel was still liquid and was boiled for an additional 15 minutes.

Upon cooling the contents of the reaction vessel, the reaction mass solidified to a straw colored solid and, by analysis, it was shown to be a mixture of an intermediate liquid polymer of furfuryl alcohol absorbed upon solid crystals of paraphenylphenol. The solid was mixed with an equal volume of water and 1% by weight of Triton 770 and the mixture was formed into a pastelike dispersion in a colloid mill.

This dye assistant was composed of which after one hour was excellent.

Example 2 Into a reaction vessel equipped with a thermometer and reflux condenser, there was placed 20 parts of monomeric furfuryl alcohol, about 10 parts of water and 1 part of a 10% solution (by volume) of phosphoric acid. This mixture was boiled about 20 to 30 minutes until the appearance of an insoluble layer as evidenced by a cloudiness in the liquid. The reaction was then neutralized with 1.4 parts of a 10% solution of sodium hydroxide in water. There resulted two phases, a lower phase comprising an intermediate polymer and an upper phase comprising water. Both phases also contained monomeric furfuryl alcohol. The water layer was removed by decantation and the intermediate polymer recovered.

Three different dye assistants were prepared from the intermediate polymer by separating the product into three equal parts and adding to each part approximately 2 parts of ortho, meta and paraphenylphenol, respectively. In the case of orthoand metaphenylphenol, the resultant dye assistants were homogeneous liquid mixtures of the intermediate polymer and phenylphenol. To that portion to which the paraphcnylphenol had been added, there was added a further quantity of water to provide a volume of water approximately equal to the combined volumes of paraphenylphenol and intermediate polymer and the resultant mixture was admixed with 1% by weight of Triton 770 (a phenol-ethylene oxide condensation product) and the mixture was homogenized in a colloid mill.

Example 3 The procedure of Example 1 was followed substituting an equal quantity of orthophenylphenol for the paraphenylphenol employed in that example. The reaction was noticeably more exothermic but otherwise the procedure was identical. The product, however, did not solidify on cooling, but instead remained a dark colored homogeneous liquid.

Example 4 The procedure of Example 1 was followed substituting an equal quantity of metaphenylphenol for the paraphenylphenol employed in that example and the dye assistant in this case similar in appearance to the dye assistant obtained in Example 3.

Example 5 A dye bath was made up containing the following constituents in 600 ml. of water:

Gm. DuPont Roracyl Dark Green B 4.8 DuPont Anthraquinone Blue SWF 1.2 DuPont Orange R0 (C. I. 161) 0.2 Copper sulfate 4.8 Dye assistant 2.4

The dye assistant was composed of a mixture of the following:

Percent Monomeric furfuryl alcohol 32 Dimer of furfuryl alcohol 1 Paraphenylphenol .66

This dye bath was brought to the boil and a piece of pure filament Orlon cloth immersed therein.

After five minutes immersion at the boil, the cloth was an excellent black but with poor penetration. As the length of immersion increased so did the penetration Theldyeing was fast to light as well as repeated washings.

Example 6 A dye bath was made up by dissolving the following ingredients in 125 gallons of water:

Dyeing Assistant of Example 1 (made with paraphenylphenol) 22 /2 The bath was thereafter transferred to'a dye jig and heated to its boiling point. Two hundred twenty-five pounds (225 lbs.) of continuous filament Orlon fabric which had been previously scoured was then dyed in the jig, taking precautions to keep the temperature of the dye bath at the boiling point, and to maintain the temperature of the fabric on the reels of the jig as close to the boiling point as possible. After the jig had been in operation for about 3 hours, the cloth had been dyed a deep black color and was removed. Subsequent examination of the cloth revealed that the dyeing was excellent and tests showed the dyeing to be fast to repeated washings and exceptionally fast to light (over 400 hours).

Example 7 The procedure of Example 6 was followed with the exception that copper nitrate was substituted for copper sulfate. The cloth was dyed a good black color but the speed of dyeing was much slower than in Example 3.

Example 8 The procedure of Example 6 was followed substituting copper acetate for the copper sulfate of Example 3. Again a good dyeing was obtained although the penetration of the dye was not as good as in the dyeing of Example 3.

Example 9 The procedure of Example was followed using, in separate experiments, the dye assistants of Examples 2, 3 and 4 in place of the dye assistant used in Example 5. Excellent dyeings were obtained in each instance.

Example 10 The procedure of Example 6 was followed except that the dyeing assistant of Example 4 was substituted for that of Example 1. An excellent dyeing was obtained.

Example 11 A laboratory raw stock dyeing machine was loaded with 500 gm. of Orlon staple filament raw stock. Water was added and brought to the boil.

The dye mixture as follows was mixed and boiled in a separate container and then poured into the machine:

7 Percent Roracyl Dark Green B; 4

Anthraquinone Blue SWF (150%) l DuPont Orange R0 1 Copper sulfate 4 The Dye Assistant of Example 1 (made with paraphenylphenol) 1O After runing at the boil for 2 hours, a further 5% of i 10 Example 12 A dye bath was made up having the following constitution:

Percent The Dye Assistant of Example 1 (made from paraphenylphenol) 10 Latyl Violet B 6 Example 13 Two dye baths were made up, A and B. Dye bath A was brought to the boil with 250 ml. of water and about 1 gram of the dyeing assistant of Example 1 (made with paraphenylphenol). 4.9 gm. of pure nylon cloth were put into this boiling bath and after 25 minutes 30 ml. of a solution of 3 gm. liter of Fast Yellow GGC were added and the bath boiled for 1 hour before removing the cloth.

Dye bath B was brought to the boil with 250 ml. of water and 30 ml. of the dye solution. 4. 9 gm. of pure nylon cloth was added and the bath boiled for 1 hour before removing the cloth.

The cloth dyed in bath A was a heavy lemon color with good penetration into the fiber. The cloth dyed in bath B was a pale yellow staining with poor penetration.

Example 14 7 Two hundred (200) ml. of monomeric furfuryl alcohol was mixed with an equal volume of water and to the resulting mixture there was added 10 ml. of a 10% by volume phosphoric acid solution. The resulting acid containing mixture was boiled until the mixture separated into two distinct layers 15 to 20 minutes) and the nonaqueous layer was separated and fractionally distilled. The fraction distilling at to C. at approximately 1 to 2 millimeters pressure was collected. The fraction was a relatively pure dimer of furfuryl alcohol in a yield equal to about 6% of the theoretical yield.

A furfuryl alcohol mixture was prepared by mixing together 15 ml. of pure distilled monomeric furfuryl alcohol and 5 ml. of the distilled dimer prepared as above.

A dye solution was prepared by mixing together 25 liters of an aqueous solution containing 30 gm. per liter of Roracyl Dark Green B (an acid dye), 12.5 liters of an aqueous solution containing 3.25 gm. per liter of DuPont Orange R0 (also an acid dye) to give a total of 50 liters of dye solution.

Several dye baths were prepared, each by mixing 50 ml. of the above-described dye solution, 25 ml. of a copper sulfate solution containing gm. of copper sulfate per liter, 0.75 ml. of the furfuryl alcohol solution described above, and 1.5 gm. of a phenolic compound within the scope of our generic formula.

Each dye bath was used to dye a 1 gram sample of fabric woven from continuous filament Orlon 81 by immersing the fabric in the bath and boiling for 20 minutes. After dyeing, the fabric was secured for 5 minutes at the boil to remove any surface dye.

The phenolic compounds used in the preparation of the dye 'bathsincluded p-cumylphenol, paraphenylphenol, tertiary butyl catechol, fi-naphthol, a-methyl-benzyl-O- phenylphenol, 4-tertiary butyl-2-phenylphenol, resorcinol, octyl phenyl, phenol, p,p-isopropylidene bis (2-isopropylphenol), nonyl phenol, cresol and thymol. Dyeings ranging from excellent to good were obtained in each case. The best dyeings were those obtained with paraphenylphenol, paracumylphenol, p,p-isopropylidenediphenol and p,p'-sec.-butylidenediphenol. v I g 1! Example A dye assistant was prepared by emulsifying 5 ml. of distilled furfuryl alcohol dimer and 170 gm. of paraphenylphenol in 250 ml. of water.

A series of dye baths were prepared, each by mixing 225 ml. of water, 50 ml. of the dye solution prepared in Example 14, ml. of a copper sulfate solution containing 120 gm. of copper sulfate per liter, 4.5 gm. of the above-described dyeing assistant and 1 ml. (1 gram if solid) of one of a variety of solvents for the furfuryl alcohol dimer.

Test dyeings were made by immersing a 1 gram sample of fabric woven from continuous filament Orlon 81 in each dye bath and boiling the bath for 20 minutes. The dyed samples were then scoured for 5 minutes at the boil in a 1% solution of Igepal CA.

The dyeings were rated excellent, good or moderate, and excellent dyeing being one in which the fabric was dyed black, a good dyeing being one in which the fabric was dyed practically black and a moderate dyeing being one in which the fabric was dyed dark green.

The dye baths containing the following solvents gave excellent dyeings:

Monomeric furfuryl alcohol Decanediol Phenylmethyl carbinol 4-hydroxy-1,3-dimethylbenzene The dye baths containing the following solvents gave moderate dyeings:

cyclohexanone methyl isobutyl carbinol tri-ethylene glycol n-octyl alcohol cyclohexanol n-heptyl alcohol benzyl alcohol n-hexyl alcohol Example 16 A series of dye baths were made according to the procedure of Example 14 using monomeric furfuryl alco- 1101 (1.5 gm.) as the solvent and varying the amounts of dimer. Test dyeings were made as in Example 14.

The following is a tabulation showing the amount of dimer used in each bath and the quality of the dyeing obtained:

Amount of Dimer (1111.) Dyeing 0.005 M odcratc. 0.0L D0. 0.025 Good. 0.05. Excellent. 0.1 Do. 0.25 Do.

An additional dye bath was made according to the same procedure but omitting the monomeric furfuryl alcohol and using 1.5 ml. of dimer. The test dyeing made from this bath was excellent.

Example 17 Two hundred (200) ml. of monomeric furfuryl alcohol was mixed with an equal volume of water and to the resulting mixture there was added 10 ml. of a 10% by volume solution of phosphoric acid. The acid-containing 12 mixture was then boiled until the formation of two distinct layers (15 to 20 minutes). The non-aqueous layer, comprisingmonomeric. fur'furyl alcohol containing about 6% of dimer, was separated.

Dye baths were prepared by mixing 50 ml. of the dye solution prepared in-Example 14, 25 ml. of copper sulfate solutiongm. per liter), 225 ml. of water and varying amounts of paraphenylphenol and the abovedescribedfurfur-yl alcohol polymerization product. Test dyeings were made from each dye bath as in Example 14.

The following is a tabulation showing the respective quantities of paraphenylphenol and furfuryl alcohol polymet in each dye bath and the quality of the dyeing resulting therefrom:

This example shows that satisfactory dyeing can be obtained even though the ratio of phenolic compound to "furfuryl alcohol dimer is widely varied.

Example .18

A dye bath was prepared by dispersing in approximately 300 ml. of water, 30 mg. of the dye Celanthrcnc Yellow GL 300% (Prototype 534), 60 mg. of a dispersing agent (Dispersol VL) and 500 mg. of the dye assistant of Example 1 (made from paraphenylphenol). The dye bath was brought to a temperature of about to F. and a 3 gm. sample of fabric woven from filament Saran was added. The dye bath was brought slowly to a boil and held at the boil for approximately one hour. The sample of Saran was dyed a brilliant yellow.

Example 19 A dye bath was prepared as in Example 18 and a 3 gram sample of material Woven of Dacron was substituted for the Saran fabric. After approximately 1 hour in the dye bath at the boil, the Dacron was dyed a good yellow and the exhaustion of the dye bath was excellent.

Example 20 A dye bath was prepared by adding to 250 ml. of water, 1 gram of the dye assistant of Example 1 (made with paraphenylphenol), and 30 ml. of an aqueous solution of the acid dye Cloth Fast Yellow GGC containing 3 gm. of dye per liter. To this dye bath there was added a 3 gm. sample of a fabric woven from filament nylon and the sample dyed at the boil for approximately 1 /2 hours. The nylon sample was dyed a good shade of yellow and examination showed the penetration to be excellent. In comparative tests where paraphenylphenol alone was substituted for the dye assistant, lighter shades were obtained.

We claim:

1. A composition comprising a mixture of 5-furfurylfurfuryl alcohol and a phenolic compound of the formula:

wherein X is a radical selected from the group consisting of hydrogen, hydrocarbon, hydroxyphenylalkyl, carboxy and halogen radicals, a is an integer from 1 to 3 and b 13 is an integer from 1 to 2, the sum of a and b not exceeding 3.

2. A composition according to claim 1 including an organic solvent for the S-furfuryl-furfuryl alcohol.

3. A composition according to claim 2 in which said solvent is furfuryl alcohol.

4. A composition according to claim 1 in which the phenolic compound comprises a phenylphenol.

5. A composition as in claim 4 wherein the phenylphenol is paraphenylphenol.

6. A composition according to claim 1 in which the phenolic compound comprises p,p'-isopropylidenediphenol.

7. A composition according to claim 1 in which the phenolic compound comprises p,p'-sec.-butylidenediphenol.

8. A composition according to claim 1 in which the composition comprises para-cumylphenol.

9. A composition comprising a mixture of furfuryl a1 cohol, S-furfuryl-furfuryl alcohol and a phenylphenol.

10. A composition according to claim 9 in which said phenol is para-phenylphenol.

11. A process for the preparation of a composition useful as a dye assistant which comprises mixing together furfuryl alcohol and a phenolic compound of the formula:

XI (H)- wherein X is a radical selected from the group consisting of hydrogen, hydrocarbon, hydroxyphenylalkyl, carboxy 13. A process according to claim 12 in which the phenylphenol is para-phenylphenol.

14. In a process for dyeing polyacrylonitrile textile materials wherein the material to be dyed is immersed in a bath containing a dye selected from the group consisting of acid and direct dyes, and a water soluble cupric salt which ionizes in aqueous solution to provide cupric ions, the improvement which comprises adding to the dye bath a quantity of S-furfuryl-furfuryl alcohol, a phenolic compound of the formula:

Xi (0H)- References Cited in the file of this patent UNITED STATES PATENTS Miner May 27, 1930 OTHER REFERENCES American Dyestuti Reporter for November 12, 1951,

page 750.

American Dyestufi Reporter for August 18, 1952, pages P510P516.

Technical Bulletin by Du Pont, Wilmington, Delaware, vol. 7 No, 3 for September 1951, pages 147, 1 48, 

14. IN A PROCESS FOR DYEING POLYACRYLONITRILE TEXTILE MATERIALS WHEREIN THE MATERIAL TO BE DYED IS IMMERSED IN A BATH CONTAINING A DYE SELECTED FROM THE GROUP CONSISTING OF ACID AND DIRECT DYES, AND A WATER SOLUBLE CUPRIC SALT WHICH IONIZES IN AQUEOUS SOLUTION TO PROVIDE CUPRIC IONS, THE IMPROVEMENT WHICH COMPRISES ADDING TO THE DYE BATH A QUANTITY OF 5-FURFURYL-FURFURYL ALCOHOL, A PHENOLIC COMPOUND OF THE FORMULA: 